In the days following Spurs' signing of Gylfi Sigurdsson from Hoffenheim, most newspaper coverage of the transfer tended to focus on why Gylfi chose Tottenham when he had the opportunity to join his former manager Brendan Rodgers at Liverpool. What these stories largely failed to discuss is whether Gylfi was any good or whether Spurs got good value for their money. Here, I aim to show that statistics indicate that Gylfi is already an excellent player and may just be the Premier League's signing of the summer.
Before analyzing Gylfi's performance for Swansea last year, it's worth noting that statistics are a very imperfect measure of performance in a sport like football for a two reasons. First, statistics in football don't capture everything that occurs on the pitch. For example, there is no way to measure a player's ability to get himself in good positions (whether offensive or defensive) via statistics. One Spurs related example of this can be seen in Gareth Bale's second goal against Norwich in the game at Carrow Road last season. In statistical terms, that play would be recorded as: "Goal - Gareth Bale" and "Assist - Luka Modric." If we watch a replay of the goal on video, however, we can see that Emmanuel Adebayor's selfless off-the-ball run dragged Norwich's right center back out of position, thereby opening up a tremendous amount of space for Bale to burst through the middle.
The second reason that statistics are an imperfect measure is that even when statistics do accurately track what is occurring on the pitch, there are number of confounding variables that make it difficult to isolate the impact of one player upon the outcome of the game. Most notably, the quality of a player's teammates will directly affect how many chances that player has to convert and how many chances that player creates for his teammates. In the 2007-08 season, Cristiano Ronaldo scored 31 goals in 38 Premier League games for Manchester United. Had he instead played for Derby County that year (who, amazingly, finished on 11 points), he would have been lucky to score half as many goals.
Even with these shortcomings, statistics in football can provide an unbiased metric by which to judge a player's performance. Consider WhoScored.com's rankings of the best premier league players last season*:
(Click on photo to zoom in)
While WhoScored's metrics vastly understate the value of defenders (not a single defender is among its top 20 players) and one might quibble with the exact order of the players above, the vast majority of these players are regarded as among the best in the Premier League last season from an attacking standpoint.
Gylfi Sigurdsson is not listed among these players because he did not make the requisite number of appearances -- WhoScored only ranks players who made more than the average number of Premier League -- which is largely due to his joining Swansea on a half-season loan. His numbers during the 19 games he played, though, indicate that he was one of the most best attacking players in the Premier League. In fact, Gylfi's WhoScored rating of 7.58 would tie Luka Modric's for third best in the Premier League had he met the requisite number of appearances.
Gylfi's effectiveness was likely boosted by the fact that he did not have to play a full season and was thus less fatigued than some of his counterparts in WhoScored's top-20 players, but there are two reasons to think that his performance could actually improve in the coming season. First, Gylfi, at just 22 years old, is younger than any player in the top-20, including our very own Gareth Bale. As the average age of the players in the top 20 is about 25 or 26 years old, there is reason to think that he will improve in the next few years.
Second, unlike any of the other players in the top 20, Gylfi played for a team that finished in the bottom half of the table. In fact, he would be only one of two players in the top-20 that did not have a teammate that was also in the top-20 (the other being Liverpool's Luis Suarez). As having better teammates tends to improve a player's performance, Gylfi could see a jump in his WhoScored rating just by playing alongside more talented players with Spurs.
In short, Gylfi Sigurdsson's performance for Swansea last season rivals that of the best players in the Premier League. Already this preseason Gylfi has been Spurs' most dangerous player and there are reasons to think he will improve even more in the coming years. This talent and his outrageously low transfer fee of £8 million may just combine to make Gylfi Sigurdsson the Premier League's best signing of the summer.
*For a glossary of WhoScored's Terms, see here: http://www.whoscored.com/Glossary